In recent years, a technology for coating on a material surface a hard film that has long life and high reliability and can be used in a carefree manner has been sought, as a protective film for mechanical components or the like. In the field of coating a hard film, a hard carbon film, particularly diamond-like carbon (DLC), has been highly evaluated as a material that enhances the slidability of a component by forming a film on a component surface. DLC is a material that contains carbon as a main component, is generally amorphous while carbon atoms have graphite sp2 bonds and diamond sp3 bonds, and exhibits intermediate physical properties between graphite and diamond. In addition, it is known to have low coefficient of friction and high wear resistance due to its film characteristics and surface smoothness and has been widely utilized as a surface coating that enhances slidability, on the sliding planes of various machines, tools, internal combustion engines and the like.
However, when external force is applied to a substrate on which a hard film such as DLC is deposited in order to improve wear resistance, the substrate is deformed to apply large distortion to the hard film and to sometimes peel off the hard film from the substrate. In order to solve this, there was suggested a protective film having a segmented shape, wherein a film formed divided into segments is deposited on a substrate (Patent Literature 1).
It is known that, to obtain such a protective film having a segmented shape, a substrate is masked using a wire gauze of a tungsten wire or the like and a protective film is thereafter deposited (Patent Literature 1). More specifically, the parts corresponding to wire gauze meshes constitute segments by performing masking using a wire gauze of a tungsten wire or the like, a lattice-shaped segmented film is obtained, and wire gauze parts, namely, the parts corresponding to the net wires of the wire gauze constitute spacings between adjacent segments.